Setting aerodrome QFE/QNH on arrival
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Gerund:
Thanks for your reply.
Under controlled airspace, I would definetly get FIS, or even try RIS (never had it before).
But as most of my flying is now in the open FIR, would u recommend I:
Thanks for your reply.
Under controlled airspace, I would definetly get FIS, or even try RIS (never had it before).
But as most of my flying is now in the open FIR, would u recommend I:
- Obtain a FIS from my local ATC (if possible?)
- Switch to Scottish Info to obtain a FIS
- Not bother with FIS and just stay on local ATC to get the standard service (do they call it Procedural Service?)
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Tomahawk, you cannot get a RIS in controlled airspace as this is a service probided outside controlled airspace.
I suggest you have a look at this and it might clear up some things http://www.caa.co.uk/docs/64/ATC_Options.pdf
If you obtain a FIS from an atsu then that would probably be best, but you probably will not get traffic, and if you get a FIS from scottish you will only get info on traffic that is talking to scottish. FIS is on of the lowest kind of service you get get, its just above an alerting service and all an alerting service is that the atsu will tell someone if you stoof in.
5 Flight Information Service
5.1 A Flight Information Service (FIS) is a non-radar service provided, either separately or in conjunction with other services, for the purposes of supplying information useful for the safe and efficient conduct of flights. Under a FIS the following conditions apply:
a) Provision of the service includes information about weather, changes of serviceability of facilities, conditions at aerodromes and any other information pertinent to safety.
b) The controller may attempt to identify the flight for monitoring and co-ordination purposes only. Such identification does not imply that a radar service is being provided or that the controller will continuously monitor the flight. Pilots must be left in no doubt that they are not receiving a radar service.
c) Controllers are not responsible for separating or sequencing aircraft.
5.2 In addition to the above, controllers will, subject to workload, provide pilots with information concerning collision hazards to aircraft operating in Class C, D, E, F or G airspace when self evident information from any source indicates that a risk of
collision may exist. It is accepted that this information may be incomplete and the controller cannot assume responsibility for its issuance at all times or for its accuracy.
I suggest you have a look at this and it might clear up some things http://www.caa.co.uk/docs/64/ATC_Options.pdf
If you obtain a FIS from an atsu then that would probably be best, but you probably will not get traffic, and if you get a FIS from scottish you will only get info on traffic that is talking to scottish. FIS is on of the lowest kind of service you get get, its just above an alerting service and all an alerting service is that the atsu will tell someone if you stoof in.
5 Flight Information Service
5.1 A Flight Information Service (FIS) is a non-radar service provided, either separately or in conjunction with other services, for the purposes of supplying information useful for the safe and efficient conduct of flights. Under a FIS the following conditions apply:
a) Provision of the service includes information about weather, changes of serviceability of facilities, conditions at aerodromes and any other information pertinent to safety.
b) The controller may attempt to identify the flight for monitoring and co-ordination purposes only. Such identification does not imply that a radar service is being provided or that the controller will continuously monitor the flight. Pilots must be left in no doubt that they are not receiving a radar service.
c) Controllers are not responsible for separating or sequencing aircraft.
5.2 In addition to the above, controllers will, subject to workload, provide pilots with information concerning collision hazards to aircraft operating in Class C, D, E, F or G airspace when self evident information from any source indicates that a risk of
collision may exist. It is accepted that this information may be incomplete and the controller cannot assume responsibility for its issuance at all times or for its accuracy.
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Final 3 Greens
Don't worry, I would certainly never do so, 'cos ....
- the puddle-jumpers that I fly, only have steam driven altis
- I have not got around to doing the full IR, I have only got an IMC
- I DO, have a strong sense of self preservation!
.... so never go below SSA/DH/MDA per se!
- the puddle-jumpers that I fly, only have steam driven altis
- I have not got around to doing the full IR, I have only got an IMC
- I DO, have a strong sense of self preservation!
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Sorry to get back to the question but, IMHO, the following should apply;
QFE - on approach/landing (Aerodrome or, if an instrument runway, Touchdown Zone Elevation)
Aerodrome QNH - when flying in a vicinity of an aerodrome.
Regional QNH - when transiting uncontrolled airspace.
Standard (1013.2 mbs) - when flying above the transition altitude.
All of these subject to the caveat "unless otherwise instructed by ATC". The key to all of this is that everyone knows which pressure setting they are using.
PS. As an air traffiker, I remember being asked my thoughts on the QNH vs QFE argument a few years ago by the then Air Officer Commanding Training Units (including Central Flying School). My response, that didn't go down too well, was:
"I don't give a toss sir, providing they all use the same pressure setting!"
QFE - on approach/landing (Aerodrome or, if an instrument runway, Touchdown Zone Elevation)
Aerodrome QNH - when flying in a vicinity of an aerodrome.
Regional QNH - when transiting uncontrolled airspace.
Standard (1013.2 mbs) - when flying above the transition altitude.
All of these subject to the caveat "unless otherwise instructed by ATC". The key to all of this is that everyone knows which pressure setting they are using.
PS. As an air traffiker, I remember being asked my thoughts on the QNH vs QFE argument a few years ago by the then Air Officer Commanding Training Units (including Central Flying School). My response, that didn't go down too well, was:
"I don't give a toss sir, providing they all use the same pressure setting!"
Last edited by Whipping Boy's SATCO; 9th Sep 2002 at 06:31.
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WBS
Question for you from the military side (I know what a lot of civilians think - myself included).
Has Regional Pressure Setting run its course in this day and age - should we not just go onto the QNH of an adjacent airfield, whether obtained by two way comms or by listening to an ATIS?
Very relevant when you consider vast portions of the Chatham ASR should actually be flown on the London QNH as it's under the London TMA.
Enjoy EGOS - you going to be operational or training?
CM
Question for you from the military side (I know what a lot of civilians think - myself included).
Has Regional Pressure Setting run its course in this day and age - should we not just go onto the QNH of an adjacent airfield, whether obtained by two way comms or by listening to an ATIS?
Very relevant when you consider vast portions of the Chatham ASR should actually be flown on the London QNH as it's under the London TMA.
Enjoy EGOS - you going to be operational or training?
CM
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CM, I agree that it would probably be better to use the QNH of the nearest airfield. However there are two problems. Firstly, at 420 kts, the aircrew would spend half their low level life (!) trying to ascertain a pressure setting. Secondly, how do you decide which is the 'closest' airfield. Sounds silly, but you would have to have designated airfields. Otherwise, you would have some aircraft on, lets say, the East Midlands QNH with others using Langar. RPS works, although I also agree that the lateral dimensions of ASRs should mirror the CAS (TMAs) they lie under. In my neck of the woods everyone seems to get on fine using the London QNH. To be really radical, if we had satisfactory LARS coverage, the easiest thing to use would be the QNH of the particular, designated, LARS unit - no need to take a service.
One option, that may reduce confusion, would be to raise the Transition Altitude. Currently you may find aircraft floating around in the same piece of airspace on 4 pressure settings. For example, an ac in a military radar pattern may be at 3000ft QFE vs transit traffic at 3000ft QNH (airfield or RPS) and another at FL40. I certainly remember having fun controlling in a combined MATZ/CTR (FFD/BZN) where our aircraft were on QFE mbs (unless in the hold at a FL) whilst the adjacent airfield was on QNH inches. I don't have to tell you that the mental gymnastics required was potentially very confusing/dangerous. Now, if we put the TA at something reasonable (let's say a minimum of 6000ft, as in the London TMA) you take away one of the options.
The other solution is to bin QFE. The RAF tried this a few years back and it worked. The only problem was that many of the aircrew still liked to see zero on landing, consequently we changed back. Bizzare, as I have just returned from a detachment where the airfield elevation was 5871ft - try setting 800mbs on the altimeter! Needless to say, QNH was the order of the day and there were no problems.
Don't know about EGOS yet - it's just one of the options that is being floated around. If I do go, it will be the School, again.
One option, that may reduce confusion, would be to raise the Transition Altitude. Currently you may find aircraft floating around in the same piece of airspace on 4 pressure settings. For example, an ac in a military radar pattern may be at 3000ft QFE vs transit traffic at 3000ft QNH (airfield or RPS) and another at FL40. I certainly remember having fun controlling in a combined MATZ/CTR (FFD/BZN) where our aircraft were on QFE mbs (unless in the hold at a FL) whilst the adjacent airfield was on QNH inches. I don't have to tell you that the mental gymnastics required was potentially very confusing/dangerous. Now, if we put the TA at something reasonable (let's say a minimum of 6000ft, as in the London TMA) you take away one of the options.
The other solution is to bin QFE. The RAF tried this a few years back and it worked. The only problem was that many of the aircrew still liked to see zero on landing, consequently we changed back. Bizzare, as I have just returned from a detachment where the airfield elevation was 5871ft - try setting 800mbs on the altimeter! Needless to say, QNH was the order of the day and there were no problems.
Don't know about EGOS yet - it's just one of the options that is being floated around. If I do go, it will be the School, again.
Last edited by Whipping Boy's SATCO; 9th Sep 2002 at 06:27.
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I wondered whether to post this or not, and then thought that, although it is not strictly applicable to the thread it might help someone doing an IMC rating who is given the question by the examiner on altitude corrections for temperature.
Although not often applicable in the UK, with winter coming and a test on a cold day, who knows what the examiner may ask?
As we know altimeters are calibrated on the ISA, which has a temperature element. If the temperature is lower than ISA then an altimeter will over read - a real life application of the 'hot to cold, don't be bold' saying.
Both Aerad and Jeppesen publish charts of values to be added to published chart altitudes in feet for instrument approaches, when the temperature is particularly low (ISA at Bournemouth 15, and a frosty morning?). They differ in the way they approach the problem (Aerad basing theirs on ISA deviations, and Jeppesen on an a/d elevation of 2000', but may be used at any aerodrome).
So just setting QNH (or QFE) for the approach may not be enough!
Hope this helps someone who may get a curved ball on their test! How nice to be able to say, with confidence, the airfield temperature is not relevant because ...............or is and I have made an adjustment 
, rather than 
Although not often applicable in the UK, with winter coming and a test on a cold day, who knows what the examiner may ask?
As we know altimeters are calibrated on the ISA, which has a temperature element. If the temperature is lower than ISA then an altimeter will over read - a real life application of the 'hot to cold, don't be bold' saying.
Both Aerad and Jeppesen publish charts of values to be added to published chart altitudes in feet for instrument approaches, when the temperature is particularly low (ISA at Bournemouth 15, and a frosty morning?). They differ in the way they approach the problem (Aerad basing theirs on ISA deviations, and Jeppesen on an a/d elevation of 2000', but may be used at any aerodrome).
So just setting QNH (or QFE) for the approach may not be enough!
Hope this helps someone who may get a curved ball on their test! How nice to be able to say, with confidence, the airfield temperature is not relevant because
...............or is and I have made an adjustment , rather than
Last edited by Gerund; 18th Sep 2002 at 16:38.
I never use QFE. VFR or IFR.
1. Altimeter has to be reset it on a missed approach
2. Obstacle heights are referenced to SL
3. Other traffic passing through the area (apart from UK circuit & Mil.
) are on some form of QNH. Even with the UK's impractical 'system', the difference between xxx feet on QNH versus Regional is less of a problem than xxx feet on QNH/regional versus QFE.
The sooner the UK ditches QFE AND establishes a common transition altitude the better.
1. Altimeter has to be reset it on a missed approach
2. Obstacle heights are referenced to SL
3. Other traffic passing through the area (apart from UK circuit & Mil.
) are on some form of QNH. Even with the UK's impractical 'system', the difference between xxx feet on QNH versus Regional is less of a problem than xxx feet on QNH/regional versus QFE.The sooner the UK ditches QFE AND establishes a common transition altitude the better.
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Gerund, you're absolutely right. There is an AIC about temperature correction but I couldn't find it because, unusually(!), the AIS web site is down. However, for those that are interested, follow the the following link to the US FAA explaination.
http://www.faa.gov/avr/arm/ac91-xx.doc
http://www.faa.gov/avr/arm/ac91-xx.doc
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Thanks for all your replies everyone.
I've just been flicking through the PPL Confuser, and I found an Air Law question on the minimum time at which you should contact an ATSU on arrival.
The answer is 15nm or 5 minutes, which ever is greater [sooner].
I think this is what my instructor must have been on about, if I contact the unit before that time, then I must wait until 15nm or 5 minutes to set the Airfield QNH.
Does anyone think otherwise?
I've just been flicking through the PPL Confuser, and I found an Air Law question on the minimum time at which you should contact an ATSU on arrival.
The answer is 15nm or 5 minutes, which ever is greater [sooner].
I think this is what my instructor must have been on about, if I contact the unit before that time, then I must wait until 15nm or 5 minutes to set the Airfield QNH.
Does anyone think otherwise?
I've always thought of QFE as Q Field Elevation ie the altimeter reads zero when on the ground within the limitations mentioned by other posters. QNH then translates to me as Q Nautical Height ie the altimeter reads your height above the ISA sea level which cues me to think flight level.
I used to set QFE for landing as I liked an instrument to confirm my height above the ground.
Now that I operate from a strip within controlled airspace and all approaches and departures are referenced to LTN's QNH, I use that as it is a waste of time to change it to QFE. Also I can't be bothered to do the mental gymnastics required. As you should know the elevation of the field your landing on, if it's beyond your mental capabilities to deduct this figure from that shown on your altimeter maybe you ought to ask yourself what you are doing sitting in the driving seat
I used to set QFE for landing as I liked an instrument to confirm my height above the ground.
Now that I operate from a strip within controlled airspace and all approaches and departures are referenced to LTN's QNH, I use that as it is a waste of time to change it to QFE. Also I can't be bothered to do the mental gymnastics required. As you should know the elevation of the field your landing on, if it's beyond your mental capabilities to deduct this figure from that shown on your altimeter maybe you ought to ask yourself what you are doing sitting in the driving seat
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tomahawk 1673
What you have been told is total B***S**t
My radar descent chart is based on Mean Sea Level. When I descend inbounds therefore they get descended on QNH so that the reference datum is the same. Seeing as I can start descending people 40 miles out from the airfield that rather puts the "only at 5 min / 15nm" theory in the dustbin very rapidly.
CM
What you have been told is total B***S**t
My radar descent chart is based on Mean Sea Level. When I descend inbounds therefore they get descended on QNH so that the reference datum is the same. Seeing as I can start descending people 40 miles out from the airfield that rather puts the "only at 5 min / 15nm" theory in the dustbin very rapidly.
CM
